Question

fiind date punctele a(-3,4),b(0,8) si c(-3,8) in reperul cartezian xoy aratati ca triunghiul abc e dreptunghic

Answer 1

$AB^2=(x_B-x_A)^2+(y_B-y_A)^2=3^2+4^2\\AC^2=(x_C-x_A)^2+(y_C-y_A)^2=4^2\\BC^2=(x_C-x_B)^2+(y_C-y_B)^2=3^2\\\Rightarrow AC^2+BC^2=AB^2\Rightarrow \triangle ABC\text{ dreptunghic \^in }C$